Intel® Celeron® Processor for PGA370 up to 1.40 GHz on 0.13 µ Process
Table 12. 3.3 Volt CMOS Output Signal Group DC Specifications
Symbol
Parameter
Nominal Voltage
Min
Max
Unit
Notes
3.3 + 5%
V
3.45
0.9
V
V
VOH
ILO
Output High Voltage
Output Leakage Current
100
µA
2.12
AGTL System Bus Specifications
It is recommended that the AGTL bus be routed in a daisy-chain fashion with termination resistors
to VTT. These termination resistors are placed electrically between the ends of the signal traces and
the VTT voltage supply. The valid high and low levels are determined by the input buffers using a
reference voltage called VREF. Refer to the appropriate platform design guide for more information
Table 13 lists the nominal specification for the AGTL termination voltage (VTT). The AGTL
reference voltage (VREF) is generated on the system motherboard and should be set to 2/3 VTT for
the processor and other AGTL logic. It is important that the baseboard impedance be specified and
held to a ±15% tolerance, and that the intrinsic trace capacitance for the AGTL signal group traces
is known and well-controlled. For more details on the AGTL buffer specification, see the
Intel® Pentium® II Processor Developer's Manual and AP-585, Intel® Pentium® II Processor
AGTL Guidelines.
Table 13. Processor AGTL Bus Specifications
1,2
Symbol
Parameter
Min
Typ
Max
Units
Notes
VTT
Bus Termination Voltage
1.1375
1.25
56
V
3
4
5
On-die RTT Termination Resistor
50
115
Ω
68
VREF
Bus Reference Voltage
2/3VTT
V
NOTES:
1. Unless otherwise noted, all specifications in this table apply to the processor up to 1.40 GHz frequency.
2. The processor for the PGA370 socket contain AGTL termination resistors on the processor die, except for the
RESET# input.
3. VTT must be held to 1.25 V ±9%. It is required that VTT be held to 1.25 V ±3% while the processor system bus
is idle (static condition). This is measured at the PGA370 socket pins on the bottom side of the baseboard.
4. Uni-processor platforms require a 56 Ω resistor and dual-processor platforms require a 68Ω resistor.
Tolerance for on-die Rtt is ±10% (56 Ω, 68 Ω resistors). Rtt is ±15% (100 Ω resistors).
5. VREF is generated on the motherboard and should be 2/3 VTT ±5% nominally. Insure that there is adequate
VREF decoupling on the motherboard.
30
Datasheet
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